Methods for testing trends in mental health – is it really possible to compare ‘like with like’?

Dr Stephan CollishawCardiff University

collishaws@cardiff.ac.uk

NCRM Research Methods Festival, Oxford, July 2014

Outline• Prevalence and burden

• Trends in diagnosis – need for epidemiological data

• Cross-cohort comparisons using symptom screens• Issues to think about in comparing ‘like with

like’• Results – adolescent mental health 1970s-

2000s

• Replication and validation

• Trends in child mental health 1999-2008

1 in 10 has a clinically significant psychiatric disorder

Impact on family life, friendships, learning Suicide and self harm (3rd leading cause of death)

Long-term prognosis Most child/adolescent disorders persist to adulthood >50% of adult mental disorders have onset <18 years Parenting, employment, social exclusion, illness, mortality Economic burden

Child psychiatric disorders: Burden and prognosis

Green et al., 2005; Kim-Cohen et al, 2003; Thapar et al., 2012; Windfuhr et al., 2008; Maughan et al., 2014

Diagnosis and treatment: autism, ADHD, depression, anxiety

• Increased help seeking, diagnosis and treatment

• Substantial increases in psychotropic medication

• Rates increased 3-5 fold per decade 1990s and 2000s

• Similar trends in many countries

Getahun et al., 2013; Kosidou et al, 2010; Olfson et al., 2014; Stephenson et al, 2013

Trends in diagnosis and treatment

• Important for planning service provision

But: Increases in referrals and diagnoses may be due to

• Increased public awareness & clinical recognition• Changing diagnostic criteria and practice• Treatment availability and perceived efficacy• ‘Medicalisation’ of normal behaviour?

Also:Majority still don’t access services

Ford et al., 2007; Potter et al., 2012

Epidemiological evidence

Two major meta-analyses of depression and ADHD

Epidemiological studies using structured diagnostic interviews

Meta-analyses: no evidence of increase in depression or ADHD

But

Variability in methods (samples, measures, diagnostic system)

Rates of depression range from <1% to >25%

‘Noise’ and variability likely to make trends difficult to detectCostello et al., 2006; Polanczyk et al., 2014

‘Like-for-like’ cross-cohort comparisons

Comparable representative cohorts with equivalent measures e.g. UK cohorts since 1960s have included Rutter/SDQ

Threats to comparability Selective attrition

Minor changes to questionnaire make a big difference Disobedience: “applies somewhat” (33%) vs “sometimes”

(75%) Calibration can be effective for aligning non-identical

instruments

Change in reportingGoodman et al., 2007

UK cross-cohort comparisons: 1974-1999

Collishaw et al, 2004

• Large nationally representative surveys (NCDS, BCS70, BCAMHS) assessed in 1974, 1986, 1999

• Age 15-16

• Parent rated Rutter or SDQ• Emotional problems• Conduct problems• Hyperactivity/inattention

• Calibration data used to align SDQ and Rutter questionnaires

• Study-specific weights using prior predictors of non-response

Emotional problems: high scores

1974 1986 19990

5

10

15

20

25

BoysGirls

% h

igh

scor

es

Cohort 3 vs. cohort 2OR = 1.72

Collishaw et al, 2004

N = 10,499 N = 868N = 7,293

Conduct problems: high scores

1974 1986 199902468

1012141618

BoysGirls

% h

igh

scor

es

Total OR = 1.56 per cohortCollishaw et al, 2004

Hyperactivity: mean scores

1974 1986 19990.25

0.5

0.75

1

1.25

1.5

BoysGirls

mea

n hy

pera

ctiv

e sc

ore

Collishaw et al, 2004

Limitations

• Only parent reports

• Imperfection of Rutter/SDQ calibration?

• Crude measures

• Are population shifts also occurring at extremes?

• What about ‘change in reporting’?

Need for replication and validation

Replication: The Youth Trends study (1986 & 2006)

Two nationally representative surveys of English youth 1986: BCS70 age 16 (N = 9,766) 2006: HSE follow-up ages 16-17 (N = 747) Identical self rated symptom screens (GHQ/Malaise)

Questions Increase in youth-reported symptoms Variation in trends by severity?

Collishaw et al, 2010

Adolescent emotional symptoms (youth reports)

1986 20060

0.5

1

1.5

2

2.5GirlsBoys

yout

h ra

ted

sym

ptom

s

ES = 0.36; p < .001

ES = 0.13; p = .06

Collishaw et al., 2010

Trends by severity

Collishaw et al, 2010

1+ 2+ 3+ 4+ 5+ 6+ 7+ 8+0

0.5

1

1.5

2

2.5

3 Chart Title

Youth emotional problem score

OR

(200

6 vs

198

6)

cohort differences significant at all thresholds, p<.01; Interaction p < .05

General shift in reporting?No change in hyperactivity

Boys Girls-0.5-0.4-0.3-0.2-0.1

00.10.20.30.40.5

19862006

hype

ract

ivity

(z-s

core

)

Collishaw et al, 2010

Do trends reflect a change in reporting?

• Shift in informant ‘thresholds’? (e.g. different expectations about normal behaviour)

• Greater willingness to report problems than in the past?

But

• Specificity of findings (no increase in hyperactivity)• Validation using external criteria desirable…

Conduct problems:Age 30 outcomes NCDS & BCS70 cohorts

Unemployed Sacked Benefits Homeless Teen parent Poor health0

1

2

3

4

NCDSBCS70

Odd

s ra

tio

Collishaw et al, 2004

Adolescent conduct problems and risk of pervasive adult dysfunction: 4+ adverse outcomes age 30

NCDS BCS700

1

2

3

4

5

Odd

s ra

tio

Collishaw et al, 2004

1999: BCAMHS 7-year olds (n = 1034) 2004: BCAMHS 7-year olds (n = 648) 2008: MCS 7-year collection (n = 13,489)

Parent & teacher SDQ symptoms & impact

Weights used to adjust for attrition and stratified design

Child mental health trends: 1999-2008

Sellers et al, in press

SDQ total and subscale mean scores all declined

Boys: total score effect size = -0.27 Girls: total score effect size = -0.12 Bigger drop in problem scores for boys than girls (p = 0.027)

Similar conclusions based on parent and teacher reports

Drop in children scoring in abnormal range (11%, 10%, 8%)

But: increase in impact of problems, e.g. classroom learning

Child mental health trends: 1999-2008

Sellers et al, in press

Conclusions

• Comparing ‘like-with-like’ essential for testing trends

• Replication and validation important

• Long-term change in adolescent mental health

• Recent data: improvements in child mental health

• Latest data 2008, what has happened since?

Barbara Maughan (KCL)

Andrew Pickles (KCL)

Robert Goodman (KCL)

Anita Thapar (Cardiff)

Ruth Sellers (Cardiff)

Frances Gardner (Oxford)

Jacqueline Scott (Cambridge)

Ginny Russell (Exeter)

National Centre for Social Research; Department of Health

Medical Research Council; Nuffield Foundation; Waterloo Foundation

Acknowledgements

Collishaw et al (2004). Time trends in adolescent mental health. J Child Psychol Psych, 45, 1350-1362.Collishaw et al (2010). Trends in adolescent emotional problems in England. J Child Psychol Psych, 51, 885-94.Costello et al (2006). Is there an epidemic of child and adolescent depression? J Child Psychol Psych, 47, 1263-71Ford et al (2007). Child mental health is everybody’s business. Child Adolescent Mental Health, 12, 13-20.Getahun et al (2013). Recent trends in childhood ADHD. JAMA Pediatrics, 167, 282-8.Goodman et al (2007). Seemingly minor changes to a questionnaire. Soc Psych Psych Epi, 42, 322-327.Green et al (2005). Mental health of children and young people in GB, 2004. Palgrave MacmillanKim-Cohen et al (2003). Prior juvenile diagnoses in adults with mental disorders. Archives General Psychiatry, 60. 709-17Kosidou et al (2010). Recent trends. Acta Psychiatrica Scandinavica, 22, 47-55.Maughan et al (2014). Adolescent conduct problems and premature mortality. Psych Med, 44, 1077-86.Olfson et al (2014). National trends in the mental health care of children, adolescents and adults. JAMA Psych, 71, 81-90Polanczyk et al (2014). ADHD prevalence estimates across three decades. Int J Epidemiology, online firstPotter et al (2012). Missed opportunities mental disorder in children of parents with depression. BJGP, 62, e487Sellers et al (in press). Trends in parent- and teacher-rated emotional, conduct. J Child Psychol Psych, in press.Stephenson et al (2013). Trends in the utilisation of psychotropic medication. Austr New Zealand J Psychiatry, 47, 74-87.Thapar et al (2012). Depression in adolescence. Lancet, 379, 1056-67.Windfuhr et al (2008). Suicide in juveniles and adolescents in the United Kingdom. J Child Psychol Psych, 49, 1155-65

References